/**
 * Safe parsing of crew video links.
 *
 * Skate crews live and die by their **full part / montage**. We deliberately
 * support only the two sources that matter for skateboarding right now:
 *
 *   - **YouTube** — full-length parts, montages, edits (the "video").
 *   - **Instagram** — clips, reels, single tricks (the "clip").
 *
 * No native / self-hosted video. Anything else is rejected so we never render
 * an untrusted iframe.
 */

export type CrewVideoSource = 'youtube' | 'instagram';

export interface ParsedCrewVideo {
  source: CrewVideoSource;
  /** Sandboxed embed URL safe to drop into an <iframe>. */
  embedUrl: string;
  /** Canonical watch/permalink URL (https) for "open externally". */
  url: string;
  /** YouTube video id / Instagram shortcode, when known. */
  id?: string;
}

/** YouTube thumbnail (hqdefault) for a video id — nice poster before play. */
export function youtubeThumb(id: string): string {
  return `https://i.ytimg.com/vi/${encodeURIComponent(id)}/hqdefault.jpg`;
}

function extractYouTubeId(u: URL): string | null {
  const host = u.hostname.replace(/^www\./, '').toLowerCase();

  // youtu.be/<id>
  if (host === 'youtu.be') {
    const id = u.pathname.split('/').filter(Boolean)[0];
    return isYtId(id) ? id : null;
  }

  if (host === 'youtube.com' || host === 'm.youtube.com' || host === 'youtube-nocookie.com') {
    // watch?v=<id>
    const v = u.searchParams.get('v');
    if (v && isYtId(v)) return v;
    // /embed/<id>, /shorts/<id>, /v/<id>, /live/<id>
    const parts = u.pathname.split('/').filter(Boolean);
    if (parts.length >= 2 && ['embed', 'shorts', 'v', 'live'].includes(parts[0])) {
      return isYtId(parts[1]) ? parts[1] : null;
    }
  }
  return null;
}

function isYtId(id: string | undefined | null): id is string {
  return !!id && /^[a-zA-Z0-9_-]{6,20}$/.test(id);
}

/** Extract an Instagram post/reel shortcode. */
function extractInstagramShortcode(u: URL): string | null {
  const host = u.hostname.replace(/^www\./, '').toLowerCase();
  if (host !== 'instagram.com' && host !== 'instagr.am') return null;
  const parts = u.pathname.split('/').filter(Boolean);
  // /p/<code>, /reel/<code>, /tv/<code>
  const idx = parts.findIndex((p) => ['p', 'reel', 'reels', 'tv'].includes(p));
  if (idx === -1) return null;
  const code = parts[idx + 1];
  if (!code || !/^[a-zA-Z0-9_-]{5,30}$/.test(code)) return null;
  return code;
}

/**
 * Parse a user-supplied URL into a safe crew-video embed. Returns null unless the
 * URL is a recognised YouTube or Instagram link over http(s).
 */
export function parseCrewVideo(raw: string | undefined | null): ParsedCrewVideo | null {
  if (!raw) return null;
  const trimmed = raw.trim();
  if (!trimmed) return null;

  let u: URL;
  try {
    u = new URL(trimmed);
  } catch {
    return null;
  }
  if (u.protocol !== 'https:' && u.protocol !== 'http:') return null;

  const ytId = extractYouTubeId(u);
  if (ytId) {
    return {
      source: 'youtube',
      id: ytId,
      embedUrl: `https://www.youtube-nocookie.com/embed/${ytId}?rel=0&modestbranding=1`,
      url: `https://www.youtube.com/watch?v=${ytId}`,
    };
  }

  const igCode = extractInstagramShortcode(u);
  if (igCode) {
    return {
      source: 'instagram',
      id: igCode,
      embedUrl: `https://www.instagram.com/p/${igCode}/embed`,
      url: `https://www.instagram.com/p/${igCode}/`,
    };
  }

  return null;
}

/** Cheap validity check for form inputs. */
export function isCrewVideoUrl(raw: string | undefined | null): boolean {
  return parseCrewVideo(raw) !== null;
}